In winter sports such as ice skating and hockey, the blades of an ice skate are the point of contact for all of the forces generated in turns, spins, jumps, etc. Known ice skate blade profiles typically have a convex shape along a length of the skate blade known as a rocker radius (often along with a second portion near each edge having a second radius or entry radius). Known ice skate blade profiles also have a concave (circular) profile across the bottom of the blade, and this profile defines two edges along the length of the blade. A skater can use either of these two edges in executing maneuvers on the ice surface.
Skate blades for different uses differ from one pair to another. Competing requirements for different applications has made the manufacture of skate blade profiles considered to be part art and part science. The operator of a machine which makes a blade profile is required to first dress the grinding wheel to have the desired contour and then ensure that during the grinding process a centerline of the profile on the wheel coincides with a centerline of the blade along its full length. If this is not done, then an irregular groove will be created along the length of the blade, with one edge being higher/lower than the other.
The dressing of the skate sharpening grinding wheel is traditionally carried out using a single point diamond dresser that is swung in a circular arc across the surface of the spinning grinding wheel about an axis perpendicular to the axis of rotation of the grinding wheel to give the wheel a convex surface with a radius of between ¼ inch and 2 inches. This technique creates the circular arc profile on the grinding wheel for grinding a complimentary concave profile across the width of the skate blade.
Limiting the blade profile to a circular, concave shape restricts a range between the maximum depth of the concave, circular profile, h, and the included angle, θ measured between the vertical side edge and a line formed generally tracking the concave profile near a bottom of the side edge. These two variables, h and θ, are interconnected by the following equation for the edges even condition:
Where:
r—is the radius of the circular arc in the bottom of the skate blade,
w—is the width of the skate blade,
h—is the maximum depth of the circular arc,
θ—is the edge angle between the vertical side edge of the skate blade and a tangent line formed tracking the circular arc at the bottom of the side edge.h=r(1−cos {a sin [w/2r]})  (1)θ=90°−a sin(w/2r)  (2)
For a hockey skate blade, typically w=0.110 inches. Given this limitation on the width, and that the known profiles have a radius, a table can be developed with a list of corresponding r, h and θ values:
Radius, r (in)Depth, h (in)Edge Angle, θ0.2500.0061377.29°0.5000.0030383.68°0.7500.0020285.79°1.0000.0015186.85°1.2500.0012187.48°1.5000.0010187.90°1.7500.0008688.12°2.0000.0007688.42°
Smaller radii provide better turning ability along with slower glide speeds, while larger radii provide superior glide speeds along with poorer turning ability. However, with a circular blade profile, the range of edge angles, θ, and depths, h, is very limited. It would be desirable to provide an ice skate blade with profiles having greater variation.
Some alternative ice skate blade profiles are known. For example, Canadian Patent Publication 2,173,001 to Danese discloses an ice skate blade with multiple irregular angled edges along the bottom of the blade. Such an ice skate blade profile is impractical in that it will be very slow and provide poor turning ability. Canadian Patent Publication 1,179,696 to Redmond et al discloses various ice skate blade profiles many of which impractically have a center portion of the bottom extending below the side edges. Below is understood here to refer to the direction towards the ice when a skater is wearing a skate with an ice skate blade. Such ice skate blade profiles will be very unstable and provide questionable lateral control.